It has been known for some time to provide a so called “driver air-bag” in a motor vehicle for deployment, during a crash situation, to offer a level of protection to the driver of the motor vehicle. Such driver air-bags are typically almost invariably stored, prior to deployment, in an air-bag housing mounted in the region of the hub of the steering wheel of the vehicle.
Typically, a cover is provided which attaches to the air-bag housing to cover the housing. The cover is generally designed to present a consistent external appearance with the remainder of the steering wheel, thereby giving a neat, “finished” appearance to the steering wheel. The cover may nevertheless be configured to allow deployment of an air-bag from within the air-bag housing; for example, the cover may be provided with one or more “split-lines” which together form a break-away panel in the cover, allowing deployment of the air-bag through the cover during a crash impact.
It has become increasingly common for at least a portion of the cover to be designed with the dual purpose of providing both an aesthetically pleasing outward appearance, whilst also functioning as a “push button” for the vehicle horn, allowing easy actuation of the vehicle horn in an emergency situation. In such arrangements, the cover is generally mounted to the air-bag housing by means of one or more spring elements and the cover and housing are, additionally, hooked to one another. Thus, the cover effectively “floats” on the housing and the cover may be depressed towards the housing, against the bias of the spring elements, to close the horn contacts and actuate the horn. Upon release of the cover after being depressed, the spring elements act to return the cover to its initial position prior to depression, whilst the hooking engagement between the cover and housing ensures that the cover and housing do not become disconnected as the cover returns to its initial position prior to depression.
In order to ensure that pushing of the cover does not allow the cover and housing to become unhooked from one another, the arrangement is configured such that movement of the cover towards the housing to actuate the horn is nevertheless insufficient to allow unhooking of the cover from the housing (and therefore insufficient to allow the cover and housing to be hooked to one another in the case where the cover and housing are initially separate during assembly). Thus, during assembly of the arrangement, the cover and housing must first be hooked together and the horn assembly subsequently mounted between the cover and housing. Mounting of the horn assembly in situ in this manner is relatively complicated, and therefore undesirably time consuming and expensive.